If the pH of a chemical system is 8.91, then what is the hydrogen ion activity of the system in mol H30*/L? Please answer to at least three significant figures: This means three digits after any leading zeroes, so a good answer would have a form such as 0.0000XYZ or 0.0XYZ mol H30*/L, where XYZ are the significant figures.

Considering the calculated amount of lowering that would occur when we add 5 g of salt and 5 grams of sugar which would be more effective per gram of solute added?    Sugar or Salt

You made a pH 9.0 buffer solution at 25° C by mixing NaOH and histidine (HisH) to give a solution that is 0.200 M in total concentration of histidine. Deprotonation constants and enthalpies (heats) of deprotonation at 25°C Compound Deprotonation Histidine Water ▼ +H3NRH+COOH+H₂NRH COO + H+ +H3NRH+COOH3NRCOO¯ + H+ +H3NRCOO →H₂NRCOO + H H₂O-OH + H¹ Part O [Na] = Calculate the concentration of Na+ at 45 °C. Express your answer using two significant figures and include the appropriate units. Submit [H+] = 0 Ti μA Value Part N Request Answer μA Calculate the concentration of H+ at 45 °C. Express your answer using two significant figures and include the appropriate units. Value Submit Request Answer μA [OH-] = Value Submit Request Answer pK A, H° (kJ mol ¹) 1.80 6.04 9.33 14.00 Units 4 Units Calculate the concentration of OH at 45 °C. Express your answer using two significant figures and include the appropriate units. Units 29.9 46.6 55.82 ? ? ?

Iron (II) fluoride needs to be precipitated from a 77.07 L tank.  If the concentration of iron (II) cation in the tank is 0.0330 M, how many grams of potassium fluoride must be added to the tank so that precipitation may begin?  The Ksp of iron (II) fluoride is 2.36 x 10-6.  (3sf)